Test machine failure check and elimination

The testing machine, in a broad sense, is an instrument that verifies the quality or performance of a product or material according to design requirements before it is put into use.

1. The oil supply valve has a low stiffness of the spring or a blockage of the throttle needle cavity. The main performance: each load can only reach a certain load, when the load can no longer rise, the oil return to the oil pipe is large.

Remedy: Replace the stabilizer spring with appropriate stiffness or clean the dirt.

2. The gap between the oil supply valve damping needle and the orifice is too small. The main performance: each load can only reach a certain load, when the load can no longer rise, the oil return valve of the delivery valve is large.

Remedy: Take out the damper needle and use a file to remove a part of the damper along the axial direction of the damper.

3. The belt that drives the oil pump is loose and slippery. After loading to a certain load, it can no longer rise, and the oil return valve has no oil flowing out, and the oil pump has no working sound.

Remedy: Loosen the motor fixing screw, adjust the position, tighten the belt, and tighten the motor fixing screw. If the belt is too deformed, you have to replace it with a new one.

4. The viscosity of the oil used in the test machine is too low (the oil is always flowing out of the return valve of the delivery valve when loading). Generally used medium-viscosity mineral oil, no water, acid and other mixtures, does not decompose at room temperature, does not become thick, if necessary, can be measured with a viscometer. Improper use of oil can clog valves and oil lines and can cause vibration or leaks in the pipeline. It is best to use oil as required by the instructions.

5. The oil pressure system is seriously leaking. The oil leakage of the oil system is generally present at the connection of the buffer valve, the return valve, the oil supply valve, the oil pump and the pipeline. After the pad is added, the screw can be tightened. If the gasket is broken, it must be removed and replaced with a new one. The gasket should be made of copper or aluminum alloy.

6. The fuel tank is not enough. When loaded to a certain load, the oil return valve of the oil delivery valve has a sound of “噗” and “噗”, and there is little oil and bubbles. When the load can no longer rise, the return pipe has no oil flowing out.

Remedy: Add oil to the test engine tank until you see that the oil level reaches half of the oil sight.

7. The oil collector of the oil pump is not pressed against the pump body. In this way, each load can only reach a certain load, and the load can no longer rise, and the oil return valve has no oil flowing out.

Remedy: Tighten the fixing screws at the rear of the pump with a wrench. If there is still a problem, remove the oil collector and add a gasket between the oil collector and the pump body.

8. The oil pump plunger is rusted. Main performance: During the loading process, the oil return valve return oil is not continuous or fluctuating. When a certain load can no longer rise, the return pipe has no oil to flow out.

Remedy: Remove the plunger and re-polish.

9. The test machine with safety valve can automatically open when the maximum load exceeds 3%~5%, to ensure that the test machine will not be damaged due to excessive overload. When the safety valve is not properly adjusted, or the valve tip and hole are not tightly closed, Will make the pressure not high.

The adjustment method is to disassemble the safety valve adjusting screw of the testing machine, check the damage of the parts for replacement, excessive overload, screw the screw downward, and vice versa.

10. The working clearance between the working piston and the cylinder is too large, and the gap is too oily, which can be seen from the oil spill and other outlets. The method is to thicken the viscosity of the oil. If the problem cannot be solved, after the precision measurement, the piston and the cylinder should be exchanged at the production plant.

11. The force-measuring piston has a large clearance between the force-measuring cylinder and the high-tonnage position, which can be seen from the lower part of the force-measuring cylinder. Under normal circumstances, there is intermittent dripping oil when there is no dripping oil or high tonnage. If it flows out in a line, the force measuring piston should be replaced. When observing the oil leakage, pay attention to the difference between the oil leakage of the joint and the oil leakage of the cylinder plug, and the wrong judgment cannot be made due to the wrong look.

12. The piston and piston sleeve in the oil delivery valve are damaged or the spring is soft. In this way, the load that can be achieved with each load is basically unchanged, and the oil delivery valve is noisy. When the load can no longer rise, the oil return of the oil return valve of the oil supply valve is large. The piston and piston sleeve should be removed and ground. If the damage is serious, the spring should be replaced.

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